Gunnery training device



Junezo, 1950 A, L, O'CONNQR, JR 2,512,256

GUNNERY TRAINING DEVICE Filed April 13, 1948 2 Sheets-Sheet l (/Z U (IIl 0 D n E El June 2o, 195o A, L, OCONNQR,v JR 2,512,256

'GUNNERY TRAINING DEVICE Filed April-13, 1948 2 Sheets-Sheet 2 BY ePatented `une 20, 1950 UNITED: STATES PATENT OFFICE GUNNERY TRAININGDEVICE Andrew lLouis Con-nor, Jr.; Grosse Ile, Mieli; assignor to lthevUnited Statesk of America asA represented by the Secretary of the AirForde Application April 13, 19481,` Serial No. Y20,700'

1 claim. (o1. ss-ztl The invention described herein may be manufacturedand usedby or for the Government for governmental purposes withoutpayment to me of any royalty thereon.

This invention relates to a -method and a device for training aerialgunners, i. e. aviation, military or naval personnel who are to shootatflying aircraft and the like. In such actual military work, attackl maycome with great suddenness from any quarter. Y

One object of this invention is to prov-ide a method of generalapplication for simulating an attacking airplane. The method makes itpossible to produce suddenly, a moving image on a screen simulating anattacking airplane and to move a dot elsewhere in accordance with themovements of the airplane image, so that a score may be keptphotoelectrically of the proportion of the time that the airplane imageis kept in the line of sight of #a .-simulated gun.

Another object of the invention is to provide an apparatus in which themethod may be carried out. employ the method.

Another object of the invention is to provide a projection apparatus inwhich the lm-to-lens distance is not critical-fandl in which two films,traveling at right yangles toreach other, generate the dot imagefromcrossed lines.`

Referring now to the drawings:

Fig. l is a diagrammatic view showing the crossed films. It illustratesthe method of forming the dot whichis to Lbe projected andphotoelectrically observed. n

Fig. 2 isa perspective view showing the assembly of apparatus for dotimage formation and photoelectric registration.

Fig. 3 is a perspective View of the cross-film projector showing thedrive thereof.

In Fig. 1, l is a horizontally traveling motion picture iilm and l I isa vertically traveling ilm. Both lm's bear transparent lines l2 whichmay be produced by scoring the fully 'exposed and developed emulsionwith ja scriber. Black lines on an otherwise transparent lilm may v'alsobe employed. i3 and M are the bevel gears of va suitable drive for thelilmand F5 :and I6 aredrive' sprockets, I1 is a suitable shutter forturning the projected image oif and on to provide intermittent orsurprise projection. Where the lines I2-l2 meet a dot, IB is formed, andis projected. Individually, the black lines |2-I2 are too indistinct tobe noticed on the screen (not shown in this iigure) upon which the twofilms are projected, but their crossing point is suin- Other forms ofapparatus may also ciently distinct and forms a mobile dot. To this end,the focus of the projector is adjusted so that the images of both ilmsHl and Il together are formed clearly` on the'screen. A high degree ofaccuracy in focusing isy not necessary. in order to avoid scratching ofthe rllm, one is wound emulsion side in and the other emulsion side out.By such arrangement, the emulsion sides do not rub each other duringprojection. While it is preferred that the iilms should cross each otherat right anglesit'is not 'essential that accuracy in this respect beobserved.

Referring now to Fig- 2, 2U is a projection screen and 2| is a motionpicture projector arranged to: project an airplane 3i in motion atintervals onto the screen 2li to simulate an aerial attack. rTheprojector 2|: does not employ cross films as shown in Fig. lybut only asingle one from which the cross films used by a projector are producedYby'hand scribing. The projector employs the cross -rilms lil-and Ilshown in Fig. i. These films are produced by scri'bing paths on theblank exposed and developed lilm corresponding -to fthe-'airplane actionon the lm used by projector vlll.- The ,paths are produced by plottingla -series of points on each film, each point representing the locationof the airplane image on the screen 2l. frame-by frame and a pointplotted for each framel.- Firstone -iilm |'0 is completely plotted, thisbeing the uppermost film. Then the position oi' the lms is reversed, nlmil now being uppermost and a completeplot made upon it. Joining theplotted points by a line onl'each iilm forms the tracks I'2l2. Ifimerepractice in 'gun pointing is desired, withoutkeeping :an accurate checkon the score, then the cross `films 'and resulting dot -35 may beprojected directly onto a screen. However, that isfnot the preferredmethod. The one which is preferred and which will here be described is amethod ofA projecting a moving airplane and automatically :keeping scoreor at least some measurement -of the time during which a simulated lgunSli-is 'being .pointed at the .airplane under condition-sin which hitswould be scored if theainplranewerehostile.

Since the dot represents the 4airplane image y The iilms are moved.

tion can be established largely with one nlm and the variation inelevation with another.

The purpose of cross-film projector 22 is, therefor, to project a movingdot 35 on a condensing lens 23 which, for convenience, is mountedin astand 24 and is approximately rectangular. The projector 2| and theprojector 22 face in opposite direction. The moving dot 35 on lens 23 isfollowed by a, photoelectric follower 25 which comprises a finger 26mounted on a swivel stand 2. The follower 26 is arranged to follow andto move in synchronism with a simulated gun 34 (or, in usual practice,merely the sighting and controlling equipment thereof). Mechanical orelectrical linkage 36 corrects the gun 2l' and follower 26 and suchlinkage is known. Electrical linkage which is suitable is of the synchrotype or that used in the Gray Telautograph. Any mechanical equivalent ofsuch a linkage is also suitable and for short distance use is preferred.A Bowden wire arranged to transmit a push, a pull or a rotation is shownin Fig. 2.

' and 56 may be provided on all film drives to de- The finger 26 offollower 25 contains a condensing lens system (not shown) by means ofwhich light from the dot (or absence of light if the dot is projectedblack) is focused on a photocell 28 which enters a trunnion 29 tointerpose the photocell in the light path from the lens sysltem. Thefinger 26 is mounted on a universal swveling head 5l.

Electrical connections 30 of a conventional nature run from thephotocell 28 to an amplifier 3| and thence to a scoring device 32 whichmay be of any desired and suitable nature, as for example, a condenserand means for measuring its accumulated charge. Such an apparatus isbroadly, not new, and has the function of measuring the time duringwhich the dot illuminates the photocell. Such time indicates how longthe trainees aim Was correct.

Synchronism between projectors 2| and 22 is obtained by the provision ofa drive shaft 33 by which projector 22 is preferably driven fromprojector 2|. The films projected by the two projectors may be bothpositive, 0r both negative. However it is preferred to project positivefilm in projector 2| and negative film in projector 22. y

Referring now to Fig. 3, this ligure illustrates van actual embodimentof a projector capable of operation on the principle illustrated inFig. 1. The projector comprises a base 40 surmounted by a housing 4|which contains a conventional light source (not shown) A lens tube 42projects forwardly from the housing 4| as in conventional projectors. Ashutter l1 occupies a space between the rear end of the lens tube 42 andthe housing 4|, which space also accommodates the passage of crossedfilms (not shown). At top and bottom of the housing 4| there are filmreels 43 and 44 respectively, reel 44 being driven from shaft 33 by apair of pulleys 45 and 46 over which a coiled spring wire belt 4lpasses. This drive is also shown in Fig. 1. The shaft 33 drives bevelgear I4 which in turn drives a similar bevel gear I3. Both gears haveassociated with them on their drive shafts sprockets I6 and |5respeccrease friction.

In this specification and its appended claim, the words intermittent andintermittently mean-separated by a complete stop-not separated only byan interval short enough to insure persistance of vision.

I claim as my invention:

In combination in a gunnery training device, a pair of oppositelydisposed motion picture projectors, the first of said pair being aconventional projector projecting a conventional film, a drive Shaftextending from said first projector to said second projector insynchronous driving relation thereto, means in the second projector forprojecting a dot image by two driven film strips Which overlap eachother perpendicularly, each lm strip bearing an image of a curve, onecurve being representative of the vertical positioning of the image onthe conventional film, and the other curve being representative of thehorizontal position of the image on the conventional iilm, the curvesbeing marked on their respective strips so as to contrast with thebackground of the strips to a degree which would not cause a dot orcurve image on a lens when projected alone but able to form a dot imageon a lens when projected together in their overlapy ping arrangement, alens adapted to receive said dot image, a simulated gun adapted to beaimed by a trainee, a motion picture screen arranged to receive a movingimage projected by the conventional projector and to be aimed at by thetrainee, a follower including a photocell system and a linger connectedto said simulated gun by a universal linkage and adapted to be actuatedby said simulated gun through said linkage to follow said dot image onsaid lens when image is projected in a direction opposite to that` inwhich the conventional projector is disposed, and a scoring deviceactuable by said photocell system for indicating the time proportionthroughout which correctness of aim is maintained by the simulated gun.

ANDREW LOUIS OCONNOR, JR.

REFERENCES C'IED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,198,600 Sudmann Slept. 19, 19162,230,149 Weddington .lan` 28, 1941 2,392,142 Gosswiller Jan. 1, 19462,406,574 Waller et al. Aug. 27, 1946 2,442,748 Blood et al June 8, 1948

